The present invention relates to a class of macrolide compounds which are antagonists of lutenizing hormone-releasing hormone (LHRH), to pharmaceutical compositions comprising the compounds, to methods of using the compounds and to the process of making the same. More particularly, the present invention relates to 3xe2x80x2,3xe2x80x2-N-bis-desmethyl-3xe2x80x2-N-cycloalkyl-6-O-methyl-11-deoxy-11,12-cyclic carbamate erythromycin A derivatives which are antagonists of LHRH.
The gonadotropins, follicle stimulating hormone (FSH), lutenizing hormone (LH), and chorionic gonadotropin (CG) are required for ovulation, spermatogenesis, and the biosynthesis of sex steroids. A single hypothalamic hormone, gonadotropin-releasing hormone GnRH also known as LHRH is responsible for regulating the secretion of both FSH and LH in mammals.
LHRH is a decapeptide having the structure:
pyro-Glu1-His2-Trp3-Ser4-Tyr5-Gly6-Leu7-Arg8-Pro9-Gly10-NH2 
where the superscripts designate the position of each aminoacyl residue in the decapeptide chain.
LHRH is released from the hypothalamus and binds to a receptor on the pituitary gland, causing the release of LH and FSH which subsequently act on the gonads to stimulate the synthesis of steroid sex hormones. The pulsatile release of LHRH, and thereby the release of LH and FSH, controls the reproductive cycle in animals and man. Acute doses of LHRH agonists increase the levels of LH and steroidal sex hormones in both animals and humans. Paradoxically, chronic doses of LHRH agonists suppress the level of LH and steroidal sex hormones. Consequently, the effect of multiple doses of LHRH agonists is to suppress estrogen formation in females and testosterone production in males. The same effect is observed in both animals and humans after administration of either acute or chronic doses of LHRH antagonists.
In recent years considerable research effort has been expended on finding antagonists of LHRH. These efforts have produced a number of peptide LHRH antagonists, which suppress LH and reproductive hormones in mammals upon administration. See for example, M. J. Karten in xe2x80x9cModes of Action of GnRH and GnRH analogsxe2x80x9d, edited by W. F. Crowley and P. M. Conn, p. 277 (1992). The literature has reported that LHRH antagonists are useful in the treatment of a variety of conditions in which the suppression of sex steroids plays a key role including contraception, delay of puberty, treatment of benign prostatic hyperplasia, palliative treatment or remission of hormonal-dependent tumors of the prostate, the treatment of cryptorchidism, hirustism in women, gastric motility disorders, dysmenorrhea, and endometriosis.
Current LHRH antagonists are decapeptides which, because of their low oral bioavailability, are administered either intravenously or subcutaneously. Non-peptide heterocyclic antagonists have been reported in the literature, see for example, WO 95/280405, WO 95/29900, WO 97/22707, WO 97/21704 and WO 97/2103. Non-peptide LHRH antagonists have the possible advantage of improved oral bioavailability and are smaller molecules.
However, there are no known reports of macrolide compounds as LHRH antagonists in the literature. Macrolide antibiotics and macrolide prokinetic agents are known. For example, macrolide antibiotics derived from erythromycin which contain 11,12-cyclic carbamate moieties are disclosed in EP 248 279 A2. The 3xe2x80x2-N substituted erythromycin derivatives, which are effective antibacterial agents are described in EP 0 559 896 A1. Macrocyclic lactone (macrolide) prokinetic agents are known. See J. S. Gidda et al., in European Patent Application No. 0349100, published Jan. 3, 1990, which discloses 12-membered macrolides for use as gastrointestinal motility enhancers. S. Omura and Z. Itoh, in U.S. Pat. No. 4,677,097, issued Jun. 30, 1987; European Application No. 215,355, published Mar. 25, 1987; and European Application No. 213,617, published Mar. 11, 1987, disclose derivatives of erythromycins A, B, C and D which are useful as stimulants of digestive tract contractile motion. Additionally, T. Sunazuka, et al., Chem. Pharm. Bull. 37(10): 2701-2709 (1989) discloses quaternary derivatives of 8,9-anhydroerythromycin A 6,9-hemiacetal and 9,9-dihydro-erythromycin A 6,9-epoxide with gastrointestinal motor stimulating activity.
None of these references disclose novel 3xe2x80x2, 3xe2x80x2-N-bis-desmethyl-3xe2x80x2-N-cycloalkyl-6-O-methyl-11-deoxy-11,12-cyclic carbamate erythromycin A derivatives of the present invention, which are effective as LHRH antagonists.
In one aspect, the present invention relates to a compound having the formula: 
or a pharmaceutically acceptable salt or ester thereof, wherein
A is selected from the group consisting of:
(a) xe2x80x94C,
(b) xe2x80x94N, and
(c) xe2x80x94O;
X and Y are independently at each occurrence selected from the group consisting of:
(a) hydrogen,
(b) halide,
(c) alkoxy,
(d) alkyl,
(e) aryl, and
(f) substituted aryl;
R and R1 are independently selected at each occurrence from the group consisting of:
(a) alkyl,
(b) cycloalkyl,
(c) heterocylic,
(d) substituted heterocyclic,
(e) alkylcycloalkyl,
(f) substituted alkylcycloalkyl,
(g) alkylaryl,
(f) alkylheterocyclic,
(g) alkenyl,
(h) alkynyl,
m is 1, 2 or 3
R2 and R3 are independently at each occurrence
(a) hydrogen,
(b) methyl, or
R2 and R3 together form a cycloalkyl moiety, when A is C; and
n=1, 2 or 3.
In another aspect, the present invention relates to a process for preparing the compound formula I. The process comprises the steps of:
(a) reacting a compound of formula: 
xe2x80x83with sodium hexamethyldisilazide and carbonyldiimidazole to afford a compound of the formula: 
(b) reacting the compound obtained in step (a) with an amino compound of the formula: 
xe2x80x83and deprotection to afford a compound of the formula: 
c) stepwise bisdesmethylating the 3xe2x80x2-amino by treating the compound obtained in step (b) twice with iodine in presence of a base to afford a compound of the formula: 
(d) alkylating the 3xe2x80x2,3xe2x80x2-N-bisdesmethylated compound obtained in step (c) with an alkylating agent.
The compounds of the invention exhibit little or no antibacterial activity, but they bind to the LHRH receptors and are effective LHRH antagonists. Thus, these compounds are effective in the treatment of prostate cancer, endometriosis, precocious puberty and other types of diseases which are related to sex hormones.
Accordingly, in another aspect of the invention, the present invention relates to pharmaceutical compositions which are useful as LHRH antagonists and suppress LH and testosterone and estrogen in mammals.
In still another aspect, the present invention relates to a method of suppressing levels of sex hormones in male or female mammals comprising administering to a host in need of such treatment a therapeutically effective amount of an LHRH compounds in combination with a therapeutically effective amount of an antiandrogenic agent.
The terms xe2x80x9cloweralkylxe2x80x9d or xe2x80x9calkylxe2x80x9d as used herein refer to straight or branched chain alkyl radicals containing from1 to 20 carbon atoms, sometimes represented as Cx-Cy-alkyl where x and y respectively represent the minimum and maximum number of carbon atoms in the alkyl radical. Examples of loweralkyl include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, 1-methylbutyl, 2,2-dimethylbutyl, 2-methylpentyl, 2,2-dimethylpropyl, n-hexyl and the like.
The term xe2x80x9calkoxyxe2x80x9d or xe2x80x9clower alkoxyxe2x80x9d as used herein refers to a loweralkyl group, as defined above, which is bonded to an oxygen atom in an ether linkage. Examples of alkoxy include, but are not limited to, methoxy, ethoxy, isopropoxy, n-pentyloxy, t-butoxy, n-octyloxy and the like. This alkoxy radical can also contain a ring which include, but are not limited to, five or six atom ring composed of carbons, one or two heteroatoms such as nitrogen, oxygen.
The term xe2x80x9calkenylxe2x80x9d as used herein refers to a branched or straight hydrocarbon chain comprising two to twenty carbon atoms, preferably four to twelve carbon atoms, especially about eight to ten carbon atoms, which also comprises one or more carbonxe2x80x94carbon double bonds, preferably about one to three double bonds. Compounds of the invention may either have a known configuration or may exist as a mixture of isomers.
The term xe2x80x9calkynylxe2x80x9d as used herein refers to a branched or straight straight hydrocarbon chain comprising two to twenty carbon atoms, preferably four to twelve carbon atoms, especially about eight to ten carbon atoms, which also comprises one or more carbonxe2x80x94carbon triple bonds, preferably about one triple bond. Compounds of the invention may either have a known configuration or may exist as a mixture of isomers.
The term xe2x80x9ccycloalkylxe2x80x9d as used herein refers to a saturated monocyclic hydrocarbon groups having from three to seven carbon atoms in the ring, including, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and the like. The cyclic group may be optionally substituted with, for example, lower alkyl, hydroxy, halogen or an amino.
The term xe2x80x9calkylcycloalkylxe2x80x9d as used herein refers to a cycloalkyl group as defined above, appended to a loweralkyl radical. The alkylcycloalkyl group is attached to the parent moiety through the alkyl radical wherein the alkyl radical is of one to six carbon atoms. Examples include, but are not limited to, cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl and the like.
The term xe2x80x9carylxe2x80x9d as used herein refers to a mono-, fused bicyclic or fused tricyclic carbocyclic ring system having one or more aromatic rings including, but not limited to, phenyl, naphthyl, tetrahydronaphthyl, phenanthrenyl, biphenylenyl, indenyl, indenyl and the like.
The term xe2x80x9csubstituted arylxe2x80x9d as used herein refers to an aryl group as defined herein substituted by independent replacement of one, two or three of the hydrogen atoms thereon with Cl, Br, F, I, OH, cyano, mercapto, nitro, C1-C3-alkyl, halo-C1-C3-alkyl, C1-C6-alkoxy, thio-C1-C6-alkoxy, methoxymethoxy, amino, C1-C3-alkyl-amino, di(C1-C3-alkyl-)amino, formyl, carboxy, alkoxycarbonyl, C1-C3-alkyl-COxe2x80x94Oxe2x80x94, C1-C3-alkyl-COxe2x80x94NHxe2x80x94, or carboxamide; except that tetrafluorophenyl and pentafluorophenyl are also included within the definition of xe2x80x9csubstituted arylxe2x80x9d.
The term xe2x80x9carylalkylxe2x80x9d as used herein refers to an aryl group as defined above appended to an alkyl group defined above. The arylalkyl group is attached to the parent moiety through an alkyl group wherein the alkyl group is one to six carbon atoms. The aryl group in the arylalkyl group may be substituted as defined above.
The terms xe2x80x9cheterocyclic ringxe2x80x9d or xe2x80x9cheterocyclicxe2x80x9d or xe2x80x9cheterocyclexe2x80x9d as used herein refers to any 3- or 4-membered ring containing a heteroatom selected from oxygen, nitrogen and sulfur; or a 5-, 6- or 7-membered ring containing one, two or three nitrogen atoms; one nitrogen and one sulfur atom; or one nitrogen and one oxygen atom. The 5-membered ring has 0-2 double bonds and the 6- and 7-membered ring have 0-3 double bonds. The nitrogen heteroatoms can be optionally quaternized. The term xe2x80x9cheterocyclicxe2x80x9d also includes bicyclic groups in which any of the above heterocyclic rings is fused to a benzene ring or a cyclohexane ring or another heterocyclic ring (for example, indolyl, quinolyl, isoquinolyl, tetrahydroquinolyl, and the like). Heterocyclics include: azetidinyl, benzimidazolyl, 1,4-benzodioxanyl, 1,3-benzodioxolyl, benzoxazolyl, benzothiazolyl, benzothienyl, dihydroimidazolyl, dihydropyranyl, dihydrofuranyl, dioxanyl, dioxolanyl, furyl, homopiperidinyl, imidazolyl, imidazolinyl, imidazolidinyl, indolinyl, indolyl, isoquinolinyl, isothiazolidinyl, isothiazolyl, isoxazolidinyl, isoxazolyl, morpholinyl, naphthyridinyl, oxazolidinyl, oxazolyl, piperazinyl, piperidinyl, pyrazinyl, pyrazolinyl, pyridyl, pyrimidinyl, pyrrolidinyl, pyrrolinyl, pyrrolyl, quinolinyl, tetrahydrofuranyl, tetrahydropyranyl, thiazolidinyl, thiazolyl, and thienyl.
Heterocyclics can be unsubstituted or monosubstituted or disubstituted with substituents independently selected from hydroxy, halo, oxo (xe2x95x90O), alkylimino (R*Nxe2x95x90 wherein R* is a loweralkyl group), cycloalkyl, aryl, arylalkyl, and loweralkyl. In addition, nitrogen containing heterocycles can be N-protected.
The term xe2x80x9c(heterocyclic)alkylxe2x80x9d as used herein refers to a heterocyclic group as defined above appended to a loweralkyl radical as defined above. The (heterocylic)alkyl group is attached to the parent moiety through an alkyl group wherein the alkyl group is of one to six carbon atoms.
The term xe2x80x9csubstituted (heterocyclic)alkylxe2x80x9d as used herein, refers to a heterocycloalkyl group, as defined above, wherein the heterocyclic group or the alkyl group is substituted by independent replacement of one, two or three of the hydrogen atoms thereon with Cl, Br, F, I, OH, cyano, mercapto, nitro, C1-C3-alkyl, halo-C1-C3-alkyl, C1-C6-alkoxy, thio-C1-C6-alkoxy, hydroxyalkyl, methoxymethoxy, amino, C1-C3-alkyl-amino, di(C1-C3-alkyl-)amino, carboxaldehydo, carboxy, alkoxycarbonyl, C1-C3-alkyl-COxe2x80x94Oxe2x80x94, C1-C3-alkylxe2x80x94COxe2x80x94NHxe2x80x94, or carboxamide.
The term xe2x80x9cheteroarylxe2x80x9d, as used herein, refers to a cyclic aromatic radical having from five to ten ring atoms of which one ring atom is selected from S, O and N; zero, one or two ring atoms are additional heteroatoms independently selected from S, O and N; and the remaining ring atoms are carbon, the radical being joined to the rest of the molecule via any of the ring atoms, such as, for example, pyridinyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isoxazolyl, thiadiazolyl, oxadiazolyl, thienyl, furanyl, quinolinyl, isoquinolinyl, and the like.
The term xe2x80x9csubstituted heteroarylxe2x80x9d as used herein refers to a heteroaryl group as defined herein substituted by independent replacement of one, two or three of the hydrogen atoms thereon with Cl, Br, F, I, OH, C1-C3-alkyl, C1-C6-alkoxy, methoxymethoxy, amino, or C1-C3-alkyl-amino, or may also refer to a mono-oxo substituted heteroaryl compound, such as 4-oxo-1H-quinoline, for example.
The term xe2x80x9caprotic solventxe2x80x9d as used herein refers to a solvent that is relatively inert to proton activity, i.e., not acting as a proton-donor. Examples include, but are not limited to, hydrocarbons, such as hexane and toluene, for example, halogenated hydrocarbons, such as, for example, methylene chloride, ethylene chloride, chloroform, and the like, heterocyclic compounds, such as, for example, tetrahydrofuran and N-methyl-pyrrolidinone, ethers such as diethyl ether and bis-methoxymethyl ether, as well as various other compounds like dimethyl formamide, acetonitrile, acetone and ethyl acetate. Such compounds are well known to those skilled in the art, and it will be obvious to those skilled in the art that individual solvents or mixtures thereof may be preferred for specific compounds and reaction conditions, depending upon such factors as the solubility of reagents, reactivity of reagents and preferred temperature ranges, for example. Further discussions of aprotic solvents may be found in organic chemistry textbooks or in specialized monographs, for example: Organic Solvents Physical Properties and Methods of Purification, 4th ed., edited by John A. Riddick, et al., Vol. II, in the Techniques of Chemistry Series, John Wiley and Sons, NY, 1986.
As used herein, the term xe2x80x9cpharmaceutically acceptable saltxe2x80x9d refers to those salts which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of humans and lower animals without undue toxicity, irritation, allergic response and the like, and are commensurate with a reasonable benefit/risk ratio. Pharmaceutically acceptable salts are well known in the art. For example, S. M. Berge, et al. describe pharmaceutically acceptable salts in detail in J. Pharmaceutical Sciences, 66: 1-19 (1977), incorporated herein by reference. The salts can be prepared in situ during the final isolation and purification of the compounds of the invention, or separately by reacting the free base function with a suitable organic acid. Examples of pharmaceutically acceptable, nontoxic acid addition salts are salts of an amino group formed with inorganic acids such as hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid and perchloric acid or with organic acids such as acetic acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid or malonic acid or by using other methods used in the art such as ion exchange. Other pharmaceutically acceptable salts include adipate, alginate, ascorbate, aspartate, benzenesulfonate, benzoate, bisulfate, borate, butyrate, camphorate, camphorsulfonate, citrate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptonate, glycerophosphate, gluconate, hemisulfate, heptanoate, hexanoate, hydroiodide, 2-hydroxy-ethanesulfonate, lactobionate, lactate, laurate, lauryl sulfate, malate, maleate, malonate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, nitrate, oleate, oxalate, palmitate, pamoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, stearate, succinate, sulfate, tartrate, thiocyanate, p-toluenesulfonate, undecanoate, valerate salts, and the like. Representative alkali or alkaline earth metal salts include sodium, lithium, potassium, calcium, magnesium, and the like. Further pharmaceutically acceptable salts include, when appropriate, nontoxic ammonium, quaternary ammonium, and amine cations formed using counterions such as halide, hydroxide, carboxylate, sulfate, phosphate, nitrate, loweralkyl sulfonate and aryl sulfonate.
Numerous asymmetric centers may exist in the compounds of the present invention. Except where otherwise noted, the present invention contemplates the various stereoisomers and mixtures thereof. Accordingly, whenever a bond is represented by a wavy line, it is intended that a mixture of stereo-orientations or an individual isomer of assigned or unassigned orientation may be present.
The preferred compounds of the invention comprise those in which R, and R1 are independently an alkyl, cycloalkyl, and heterocyclic; X and Y are independently chloro, fluoro, dioxalano, hydrogen, or alkoxy; A is xe2x80x94C; R2 and R3 are both hydrogen; m is 1 or 2 and n is 1.
Representative compounds of the invention are selected from the group consisting of:
3xe2x80x2-Desamino-(3xe2x80x2S)-N-pyrrolidinyl-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-pyrrolidinyl-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-piperidinyl-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-piperidinyl-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2S-N-(2,5-dimethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-dimethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,6-dimethylpiperidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,6-dimethylpiperidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamnino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate); and
3xe2x80x2-Desamino-3xe2x80x2-N-(2,6-biscyclopropylpiperidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diallylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diallylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-dipropylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-dipropylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamnino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diisopropylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diisopropylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-biscyclopropylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-biscyclopropylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-biscyclobutylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-biscyclobutylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-[2,5-bis(cyclopropylmethyl)pyrrolidinyl]-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate); and
3xe2x80x2-Desamino-3xe2x80x2-N-[2,5-bis(cyclopropylmethyl)pyrrolidinyl]-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate)
The more preferred compounds are selected from the group consisting of:
3xe2x80x2-Desamino-(3xe2x80x2S)-N-pyrrolidinyl-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-piperidinyl-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-piperidinyl-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2S-N-(2,5-dimethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-dimethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro,4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,6-dimethylpiperidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,6-dimethylpiperidinyl)-11-deoxy-11-[carboxy-(3-chloro, 4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3,4-dichlorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate);
3xe2x80x2-Desamino-3xe2x80x2-N-(2,5-diethylpyrrolidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate); and
3xe2x80x2-Desamino-3xe2x80x2-N-(2,6-biscyclopropylpiperidinyl)-11-deoxy-11-[carboxy-(3-chloro-4-fluorophenethylamino)]-6-O-methyl-erythromycin A 11,12-(cyclic carbamate).
Effect and Utilities of LHRH Agonists and Antagonists
The LHRH agonist and antagonist compounds of the invention are useful for treatment of precocious puberty, prostate cancer, benign prostatic hyperplasia (BPH), endometriosis, uterine fibroids, breast cancer, acne, premenstrual syndrome, polycystic ovary syndrome and diseases which result from excesses or deficiencies in gonadal hormone production in either sex of humans and animals. The LHRH antagonists of the invention are also useful for controlling reproduction in both female and males. Compounds of the invention are useful for suppressing levels of testosterone and dihydrotestosterone (DHT) in male and estrogen and estradiol in female.
In the practice of the method of this invention an effective amount of a compound of the invention or a pharmaceutical composition containing the same is administered to the human or animal in need of, or desiring, such treatment. The compound or composition may be administered by any variety of routes depending upon the specific end use, including orally, parenterally (including subcutaneous, intramuscular and intravenous administration), vaginally (particularly for contraception), rectally, buccally (including sublingually), transdermally or intranasally. The most suitable route in any given case will depend upon the use, particular active ingredient, the subject involved, and the judgment of the medical practitioner. The compound or composition may also be administered by means of slow-release, depot or implant formulations as described more fully herein below.
In general, to modulate levels of sex hormones in male or female mammals for the uses herein above described, it is expedient to administer the active ingredient in amounts between about 1 and 200 mg/kg body weight per day, preferably between 1 and 30 mg/kg body weight per day. This administration may be accomplished by a single daily administration, by distribution over several applications or by slow release in order to achieve the most effective results.
The exact dose and regimen for administration of these compounds and compositions will necessarily be dependent upon the needs of the individual subject being treated, the type of treatment, the degree of afflication or need and the judgment of the medical practitioner. In general, parenteral administration requires lower dosage than other methods of administration which are more dependent upon absorption.
A further aspect of the present invention relates to pharmaceutical compositions containing as active ingredient a compound of the present invention which compositions comprise such compound in admixture with a pharmaceutically acceptable, non-toxic carrier. As mentioned above, such compositions may be prepared for use for parenteral (subcutaneous, intramuscular or intravenous) administration, particularly in the form of liquid solutions or suspensions; for use in vaginal or rectal administration, particularly in semisolid forms such as creams and suppositories; for oral or buccal administration, particularly in the form of tablets or capsules, or intranasally, particularly in the form of powders, nasal drops or aerosols.
The compositions may conveniently be administered in unit dosage form and may be prepared by any of the methods well-known in the pharmaceutical art, for example as described in Remington""s Pharmaceutical Sciences, Mack Publishing Company, Easton, Pa., 1970. Formulations for parenteral administration may contain as common excipients sterile water or saline, polyalkylene glycols such as polyethylene glycol, oils of vegetable origin, hydrogenated naphthalenes and the like. Formulations for inhalation administration may be solid and contain as excipients, for example, lactose, or may be aqueous or oily solutions for administration in the form of nasal drops. For buccal administration typical excipients include sugars, calcium stearate, magnesium stearate, pregelatinated starch, and the like.
It is particularly desirable to deliver the compounds of the present invention to the subject over prolonged periods of time, for example, for periods of one week to one year from a single administration. Various slow release, depot or implant dosage forms may be utilized. For example, a dosage form may contain a pharmaceutically acceptable non-toxic salt of a compound of the invention which has a low degree of solubility in body fluids, for example, (a) an acid addition salt with a polybasic acid such as phosphoric acid, sulfuric acid, citric acid, tartaric acid, tannic acid, pamoic acid, alginic acid, polyglutamic acid, naphthalene mono- or di-sulfonic acids, polygalacturonic acid, and the like; (b) a salt with a poly valent metal cation such as zinc, calcium, bismuth, barium, magnesium, aluminum, copper, cobalt, nickel, cadmium and the like, or with an organic cation formed from e.g., N,Nxe2x80x2-debenzylethylenediamine or ethylenediamine; or (c) combinations of (a) and (b) e.g., a zinc tannate salt. Additionally, the compounds of the present invention or preferably, a relatively insoluble salt such as those just described, may be formulated in a gel, for example, an aluminum monostearate gel with, e.g. sesame oil, suitable for injection. Particularly preferred salts are zinc salts, zinc tannate salts, pamoate salts, and the like. Another type of slow release depot formulation for injection would contain the compound or salt dispersed or encapsulated in a slow degrading, non-toxic, non-antigenic polymer such as polylactic acid/polyglycolic acid polymer for example as described in U.S. Pat. No. 3,773,919. The compounds of the invention or, preferably, relatively insoluble salts such as those described above may also be formulated in cholesterol matrix pellets, particularly for use in animals. Additional slow release, depot or implant formulations, e.g. liposomes, are well known in the literature. See, for example, Sustained and Controlled Release Drug Delivery Systems, J. R. Robinson ed., Marcel Dekker, Inc., New York, 1978. Particular reference with respect to LHRH type compounds may be found, for example, in U.S. Pat. No. 4,010,125.
LHRH Antagonist Activity
Representative compounds of the present invention were evaluated in in vitro tests for LHRH rat pituitary receptor binding (pKI). The tests employed the methods detailed in F. Haviv, et al. J. Med. Chem., 32: 2340-2344 (1989). The receptor binding affinity (pKI) is the negative logarithms of the equilibrium dissociation constants. The results of the pKI for representative compounds of this invention are presented in Table 1.
Synthetic Methods
The compounds and processes of the present invention will be better understood in connection with the following synthetic Schemes 1 and 2 which illustrate the methods by which the compounds of the invention may be prepared. The compounds are prepared by utilizing commercially available or synthesized reagents.
Abbreviations
Abbreviations which have been used in the descriptions of the scheme and the examples that follow are: Ac for acetyl; APCI for atmospheric pressure chemical ionization; CDI for carbonyldiimidazole; CH3CN for acetonitrile; CI or DCI for desorption chemical ionization; DMF for dimethyl formamide; ESI for electrospray ionization; EtOAc for ethyl acetate; FAB for fast atom bombardment; FRIR for Fourier transform infrared spectroscopy; HPLC for high performance liquid chromatography; IR for infrared spectroscopy; MeOH for methanol; MHz for megahertz; MIC for microscope; MS for mass spectra; NaHMDS for sodium hexamethyldisilazide; NMR for nuclear magnetic resonance; Rf for retention factor; Rt for retention time; TBAF for tetrabutylammonium fluoride; THF for tetrahydrofuran; TLC for thin layer chromatography; TMS for trimethylsilyl; and TMSCl for trimethylsilyl chloride.
The starting material 6-O-methyl erythromycin A 1 (clarithromycin, commercially available as BLAXIN(copyright) from Abbott Laboratories) is protected at the 2xe2x80x2 and 4xe2x80x3 positions by reaction with a suitable hydroxy protecting reagent, such as described by T. W. Greene and P. G. M. Wuts in Protective Groups in Organic Synthesis, 2nd. ed., John Wiley and Son, Inc. 1991. Hydroxy protecting groups include, for example, acetic anhydride, benzoic anhydride, benzylchloroformate, hexamethyldisilazane, or trialkylsilyl chloride in an aprotic solvent. 
Protection of 2xe2x80x2- and 4xe2x80x3-hydroxy groups of 6-O-methyl-erythromycin A 1 as shown in Scheme 1 may be accomplished sequentially or simultaneously to provide compound 2 where RP is a hydroxy protecting group. A preferred protecting group RP is trimethylsilyl or acetyl.
Examples of aprotic solvents are dichloromethane, chloroform, DMF, tetrahydrofuran (THF), N-methyl pyrrolidinone, dimethylsulfoxide, diethylsulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamide, a mixture thereof or a mixture of one of these solvents with ether, tetrahydrofuran, 1,2-dimethoxyethane, acetonitrile, ethyl acetate, acetone and the like. Aprotic solvents do not adversely affect the reaction, and are preferably dichloromethane, chloroform, DMF, tetrahydrofuran (THF), N-methyl pyrrolidinone or a mixture thereof.
The protected compound 2 is treated with sodium hexamethyldisilazide or sodium hydride in an aprotic solvent at 0-25xc2x0 C. and carbonyldiimidazole to yield compound 3. Treatment of compound 3 with an amino compound of the formula 
either without solvent or in acetonitrile at 25-80xc2x0 C., followed by deprotection results in formation of N-substituted cyclic carbamate represented by compound 4.
Deprotection of the 2xe2x80x2- and 4xe2x80x3-hydroxy protecting groups to obtain compound 4 is carried out by the methods described by T. W. Greene and P. G. M. Wuts in Protective Groups in Organic Synthesis, 2nd. ed., John Wiley and Son, Inc. 1991. The desmethylation of the 3xe2x80x2-N-dimethyl group is accomplished by treating compound 4 with iodine in the presence of a suitable base, such as sodium acetate and a light or a heat source, followed by quench with sodium thiosulfate and work up to afford compound 5. The second methyl group is removed by treatment with iodine, a moderate base such as tribasic potasium phosphate and a light source to form the bisdesmethyl amine 6. N-Desmethylation can also be accomplished utilizing chloroformate reagents such as benzyl chloroformate, allyl chloroformate, vinyl chloroformate and the like.
Alkylation of 3xe2x80x2,3xe2x80x2-N-bisdesmethyl compound 6 is achieved by reaction with an appropriate dialdehyde, ketonealdehyde or diketone in the presence of a hydride metal such as sodium cyanoborohydride or sodium triacetoxyborohydride or in the presence of Pd/C catalyst in a protic or non-protic solvent under hydrogen atmosphere. The dialdehydes, ketonealdehydes or diketones that may be used in preparing compound 7 include, for example, succinic dialdehyde, glutaraldehyde, acetonylacetone, 2,6-heptanedione, 3,6-octanedione, deca-1,9-dien-4,7-dione, 1,5-biscyclopropyl-1,5-dione. Alkylation of 3xe2x80x2,3xe2x80x2-N-bisdesmethyl compound 6 can also be achieved by the reaction with an appropriate alkylating agent in the presence of a base by the methods known in the art to afford compound 7. 
Scheme 2 illustrates a specific embodiment of Example 1 which involves treatment of 2xe2x80x2-acetyl-6-O-methyl erythromycin A 8 with trimethylsilyl chloride to afford compound 9. Compound 9 is treated with sodium hexamethyldisilazide and carbonyldiimidazole to yield the 12-O-acylimidazole derivative 10, which is subsequently reacted with 3,4-dichlorophenethyl amine to form the 11,12-cyclic carbamate derivative. The 11,12 cyclic carbamate so obtained is treated with methanol to give compound 11. Deprotection of the 4xe2x80x3-protected hydroxy group is achieved by methods known in the art to yield compound 12. Treatment of compound 12 with iodine in the presence of sodium acetate followed by quenching the reaction mixture with sodium bisulfite affords compound 13. The second desmethylation is achieved by treating 13 with iodine, tribasic potassium phosphate and a light source to form the bisdesmethyl amine 14. The alkylation of the 3xe2x80x2-nitrogen is achieved by reaction with succinic dialdehyde in the presence of sodium cyanoborohydride in methanol and a few drops of acetic acid to afford the final product, compound 15. 